Weather
Cloudy Visibility: 8 nm
Wind direction: 100
Wind speed: 7 knots
Seawater temperature: 10 degrees C
Sea level pressure: 1011.8 mb
Temperature dry bulb: 10.6 degrees C
Temperature wet bulb: 10.0 degrees C
Science and Technology Log
I went to the Pilot House this morning to continue working on my navigating underway skills and discovered that the cruise plan had changed and that the ship will anchor in Eagle Harbor tonight. I am given the two course plot accordingly. According to the weather report, we will run into some bad weather on route to Eagle Harbor.
The rain is shown by the heavy dotted areas and the ship is anchored in the center.
Personal Log
Here are some photographs of daily activities aboard the NOAA Ship RAINIER.
Survey boats in the Northeast BightShawn Gendron, Hydrographic Assistant Survey Technician, processing survey line data
Weather
Clear Visibility: 10 nm
Wind direction: 200
Wind speed: 10 knots
Seawater temperature: 11.1 degrees C
Sea level pressure: 1011.4 mb
Temperature dry bulb: 13.3 degrees C
Temperature wet bulb: 11.1 degrees C
Science and Technology Log
I continue practicing navigation underway using radar and dead reckoning. Three of the fixes I checked fall right on the ship’s course. A few others fall within an acceptable error. The swells were a little rough so I take a break from the radar screen and charts until the late afternoon.
The NOAA Ship RAINIER anchors in Northeast Bight, Nagai Island for the night.
In the pilot house, from left to right, ENS Olivia Hauser, Jr Officer, ENS Megan McGovern, Jr Officer, Umeko Foster, and Jacquelyn Hams
Weather
Partly cloudy
Visibility: 10 nm
Wind direction: 330
Wind speed: 10 knots
Sea Wave height: 0-1
Seawater temperature: 10 degrees C
Sea level pressure: 1016.5 mb
Temperature dry bulb: 12.2 degrees C
Temperature wet bulb: 10.6 degrees C
Science and Technology Log
Today I practice the skills necessary to navigate underway using radar navigation and dead reckoning. Radar navigation is a technique by which radar is used to determine the distance from the ship to known points on shore. These distances are then transferred to the chart to plot the ship’s position. Radar navigation is useful for fixing the ship’s position in reduced visibility, and as a check against visual means even in good weather. Dead Reckoning is a method of estimating the ship’s position based on assumptions about ship speed, heading, length of time underway on that heading, and other influences such as current or wind.
In general, if the speed of the ship and length of time the ship has been on a particular heading is known, the simple formula “Distance = Speed x Time” is used to estimate distance run. To plot the estimated current ship position using dead reckoning, we lay down an approximate track line on the chart from our assumed starting position in the direction the ship was traveling and for the distance the ship traveled in nautical miles. Dead Reckoning is used by NOAA as a backup to the more accurate means of fixing the ship’s position in the event that all electronics are lost and there are no visible landmarks for reference. The navigators aboard the RAINIER also keep dead reckoned position, or “DR”, current on their charts to use as a check on their position fixes. The interpretation of radar images, radar navigation, and dead reckoning are definitely acquired skills that I plan to work on during the remainder of this cruise.
Personal Log
The RAINIER held a beach party after dinner. We were transported to a nearby beach in Northeast Bight on Nagai Island for a few hours of relaxation. The beach is rocky and composed of andesite and tuff. The andesite is much lighter in color than I usually see. I wasn’t sure it was andesite until I found a rock with the characteristic needle-like pieces of shiny black basalt (obsidian).
TAS Jacquelyn Hams charting a course in the Pilot House
Weather
Partly cloudy
Visibility: 10 nm
Wind direction: 255
Wind speed: 10 knots
Seawater temperature: 9.40 degrees C
Sea level pressure: 1016.8 mb
Temperature dry bulb: 11.7 degrees C
Temperature wet bulb: 10.6 degrees C
Science and Technology Log
The RAINIER is anchored in Porpoise Harbor while boats conduct hydrography surveys. I completed my first navigation assignment given to me by ENS Nate Eldridge, RAINIER Junior Officer. The assignment is to plot a course from our anchorage at Porpoise Harbor to our next anchorage at Northeast Bight. ENS Eldridge provided me with the detailed sail plan showing waypoints, distances, bearings (directions) as a way of checking my work.
Sail plan to Northwest Bight
NOAA has several checks and balances that navigators use to assure accuracy of charts. After a rough start, I begin to get the hang of it. NOAA charts are extremely accurate and a larger than normal dot and circle can result in an error of one or two degrees. Most of my navigation skills are related to recreational boating or classroom teaching, both of which allow a large margin for error. Toward the end of the exercise I begin to make small but precise points. ENS Eldridge revises the sail plan due to a change in weather and I complete the revised chart. When pressed, ENS Eldridge said he would give me and A- on my course! I feel that working with the NOAA navigation officers here will provide me with a skill I can take back to the classroom.
Portion of bathymetric chart for Nagai Island and Unga Island with course plotted to Northeast Bight
